Naproxen sodium is a non-steroidal anti-inflammatory drug (NSAID). As with other NSAIDs, naproxen sodium works by blocking the production of the substances in the body that cause pain and inflammation. It is an effective analgesic. When taken as directed, naproxen sodium is an effective pain reliever. However, you need to talk to your doctor or pharmacist before use if you are under a doctorâ€™s care for a serious condition, are taking another drug, or are taking any other product that contains naproxen sodium or any other pain reliever or fever reducer. You can find naproxen sodium as a pain reliever in over-the-counter (OTC) cough-cold medicines, and in some prescription anti-inflammatory drugs. It is used for the temporarily relief of minor aches and pains, including headache, muscular aches, menstrual cramps, toothache, backache, and the minor pain of arthritis and the common cold. It also temporarily reduces fever.